drawing git history with graphviz

graph.dot

digraph G {
	rankdir="LR";
	bgcolor="white";
	node[width=0.15, height=0.15, shape=circle, color=black, fontcolor=black];
	edge[weight=2, arrowhead=none, color=black];

	master[shape=box];
	topic[shape=box];

	node[group=main];
	1 -> 2 -> 3 -> 4 -> 5;
	5 -> master [style=dotted];
	node[group=topic];
	2 -> 6 -> 7 -> 4;
	7 -> topic [style=dotted];
}